1. Field of the Invention
In one of its aspects, the present invention relates to a novel fluid treatment device. In another of its aspects, the present invention relates to a novel process for reducing the level of a chemical compound in a fluid.
2. Description of the Prior Art
Fluid treatment devices and processes are known.
Two approaches used in such devices and processes relates to adsorption and/or photocatalysis. Alone or in combination, these approaches are particularly suitable to remove or reduce the levels of a target contaminant in a fluid. In some cases, it is know to support a photocatalyst on an adsorbent. These approaches have met with some success to treat water containing one or more chemical compounds such as organic contaminants.
Much of the prior art has been devoted to improving the materials used to adsorb and/or photocatalyze the chemical compound(s) contained in the fluid. Generally, it has been seen to be desirable to increase one or more of the following properties of the material: adsorption capacity, adsorption rate and rate of photocatalysis.
Despite the advances made in the art, there is still room for improvement. For, example it would be desirable to have a practical and efficient device and process for treating fluid which did not necessarily require the use of high end adsorbents and photocatalysts. It would be further advantageous if the adsorption and photocatalysis could be conducted in the same fluid treatment zone.
It is an object of the present invention to provide a novel fluid treatment device which obviates or mitigates at least one of the above-mentioned disadvantages of the prior art.
It is another object of the present invention to provide a novel process for treatment of fluid which obviates or mitigates at least one of the above-mentioned disadvantages of the prior art.
Accordingly, in one of its aspects the present invention provides a fluid treatment device for reducing the level of a chemical compound in a fluid comprising:
a fluid inlet;
a fluid outlet;
a flow-through fluid treatment zone-having comprising: a radiation source, an adsorbent and a photocatalyst;
the fluid treatment zone reversibly operable between a first mode in which the fluid flows in a first direction and at least a portion of the chemical compound is adsorbed on the adsorbent; and a second mode in which the fluid flows in a second direction different from the first direction in which the adsorbed chemical compound is exposed to radiation from the radiation resulting in photooxidation of the chemical compound.
In another of its aspects, the present invention provides process for reducing the level of a chemical compound in a fluid, the process-comprising the steps of:
feeding the fluid to a fluid treatment device comprising a fluid inlet; a fluid outlet and a flow-through fluid treatment zone disposed between the fluid inlet and the fluid outlet, the fluid treatment device comprising: a radiation source, an adsorbent and a photocatalyst,
feeding the fluid in a first mode in which the fluid flows in a first direction and at least a portion of the chemical compound is adsorbed on the adsorbent; and
feeding the fluid in a second mode in which the fluid flows in a second direction different from the first direction in which the adsorbed chemical compound is exposed to radiation from the radiation resulting in photooxidation of the chemical compound.
The present invention deviates from the conventional approaches to improve materials in that the present invention relies on practical and efficient cycling between adsorption mode and photocatalysis mode (this can also be consider to xe2x80x9cde-adsorptionxe2x80x9d mode or xe2x80x9cregenerationxe2x80x9d mode). Thus, the present fluid treatment device is operable between a first adsorption mode and second photocatalysis (or regeneration or de-adsorption mode). In the adsorption mode, the chemical compound of interest is removed from the fluid being treated and is loaded onto the adsorbentxe2x80x94in this mode the adsorbent preferably is in the form of a fixed bed. When the loaded adsorbent reaches a predetermined threshold, fluid flow through treatment zone is, in a preferred embodiment, reversed and radiation from the radiation source serves to photocatalyze the loaded adsorbentxe2x80x94in this mode the photocatalyst preferably is in the form of a fluidized bed. Preferably, the adsorbent and the photocatalyst are comprised in the same material (e.g., the photocatalyst is supported on the adsorbent).